Does the description disclose side effects, auth requirements, rate limits, or destructive behavior?

No annotations are provided, so the description carries the full burden. It only states the function without disclosing any side effects, constraints, or context (e.g., that it's a hint, that results are discarded, or that it makes an external API call). The description is essentially a bare assertion of functionality.

Agents need to know what a tool does to the world before calling it. Descriptions should go beyond structured annotations to explain consequences.

Is the description appropriately sized, front-loaded, and free of redundancy?

The description is a single sentence with no filler, which is concise and front-loaded with the core purpose. It earns its place by being to the point, though it sacrifices depth for brevity.

Shorter descriptions cost fewer tokens and are easier for agents to parse. Every sentence should earn its place.

Given the tool's complexity, does the description cover enough for an agent to succeed on first attempt?

Given the tool has 9 optional parameters and no output schema, the description is severely incomplete. It does not explain how to use the tool, what the primary 'city' parameter is for, or why other unrelated parameters are present. An agent cannot reliably call this tool based on the description alone.

Complex tools with many parameters or behaviors need more documentation. Simple tools need less. This dimension scales expectations accordingly.

Does the description clarify parameter syntax, constraints, interactions, or defaults beyond what the schema provides?

Schema description coverage is 100%, so the parameters are documented in the schema. The description adds no additional meaning about the parameters, which is acceptable per the baseline. However, the description does not clarify why many unrelated parameters (ref, url, json, etc.) exist in a weather tool, leaving the agent uncertain about which are relevant.

Input schemas describe structure but not intent. Descriptions should explain non-obvious parameter relationships and valid value ranges.

Does the description clearly state what the tool does and how it differs from similar tools?

The description clearly states it provides the current temperature for a city via Open-Meteo, which is a specific verb+resource. However, it doesn't explicitly say 'get' or 'retrieve', and it doesn't differentiate from siblings beyond the weather context, which is already unique among the listed tools.

Agents choose between tools based on descriptions. A clear purpose with a specific verb and resource helps agents select the right tool.

Does the description explain when to use this tool, when not to, or what alternatives exist?

There is no guidance on when to use this tool versus alternatives, no mention of prerequisites, and no exclusions. The agent is left to infer that it is for weather queries, but no explicit routing is provided.

Agents often have multiple tools that could apply. Explicit usage guidance like "use X instead of Y when Z" prevents misuse.